Preheat oven to moderate 180 c.
Place all the sheets of pastry onto the work surface.
Using a sharp knife or scissors, cut filo widthways into three even pieces.
Brush one piece with combined butter and oil, top with a second piece.
Brush one narrow end with butter and oil mixture.
Place 2 tablespoons of custard 2cm in from opposite end.
Roll pastry over filling.
Fold ends in towards filling; roll to end of pastry.
Repeat with remaining pastry and custard.
Arrange rolls onto prepared tray about 2cm apart.
Brush with remaining butter and oil mixture.
Bake 30 minutes or until pastry is puffed and lightly golden.
Serve warm, dusted with combined icing sugar and cinnamon.

While working keep filo pastry covered with a clean damp cloth to prevent drying out.
Cover the assembled rolls to prevent the pastry drying.